Artillery projectile



Nov. 22, 1938. M. vos

ARTILLERY PRCJECTILE Filed March 27, 1 936 Patented Nov. 22-, 1938 UNITED STATES AB'I'ILLERY PDOJECT'ILE Maurltz Vos, Stockholm, Sweden, asslgnor to Telefonaktiebolaget L. M. Ericsson, Stockholm, Sweden, a company of Sweden Application March 27, 1936, Serial No. 71,294 In. Sweden April 2, 1935 14 Claims. (CL 102-29) In shooting with such shells or other artillery projectiles carrying a bursting charge which are intended to burst in the air the point of time for bursting is determined through the agency of a time fuse or the like arranged in the projectile and through a timing device through the setting of which due regard can be taken to the firing range, to the time required for loading, and to other factors which have an influence on the computed time for thebursting reckoned from the moment of discharge. On account of the diiflculties connected with the accurate estimation of said time, there being unavoidable sources of error both in the time-computing proper and avoid thediflicuities inherent in the use of time fuses or the like and proposes to cause instead the bursting of the projectile throughan arrangement which is actuated through a reaction on the projectile from the target and which is capable of action only when the projectile is near the target or passes the target respectively- The invention consists substantially therein that the projectile is provided with a source of light as well as with a receiving arrangement sensitive to rays of light which receivingarrangement is capable of being actuated by the light which is emitted from said source of light and is reflected from the target and which in turn actuates the igniting composition of the projectile for the purpose of causing the projectile 'to burst. The light receiving arrangement, which can consist of a photoelectric device provided with a suitable optical equipment, should preferably be screened off in such manner that it can be actuated only by light striking the projectile from the sides. This screening off of the light source prevents on the. one hand that the source of light actuates the the invention.

In the drawing Fig. 1 represents an axial section of one form of the projectile;

Fig. 2 a similar view of a modification; and Fig. 3 is plan view of Fig. 2.

with a light receiving arrangement according to Fig. 4 is an axial sectional view of a projectile showing a modified arrangement of the light emitting and light receiving openings.

Referring to Figure 1, the source of light is positioned in the front portion or nose of the shell or other projectile I and consists of a cartridge 2 consisting of some substance which burns with an intensive light, for example magnesium or aluminium powderor a mixture of such substances with other substances. When the cartridge burns the light emitted radiates through openings 3 provided in the walls of the shell and preferably evenly distributed about the periphery thereof whereby such a screening of! of the source of light is obtained that the light radiates substantially only in lateral directions. The ignition of the light source is preferably effected under control of an ignition retarding device of some suitable kind, such as shown in Figure 4. The light emitting substances may for example be ignited by a resistor 25 which is included in an electric circuit supplied with current by a battery 26. The resistor is heated to the ignition temperature by the current passing therethrough when the circuit is closed. The ignition circuit is normally open and is closed when a conducting segment 29 arranged on a clock actuated rotatable insulated disc 30 bridges the contact brushes 2'! and 28. The disc 30 is normally held against rotation by a detent 3| which carries a weight so that due to the inertia of the mass the detent releases the disc when the projectiieis fired. The clock operated disc 30 and the segment 29 cause the circuit to be closed through the resistor 25 and thus the light emitting substance is ignited.

The light receiving arrangement consists in the illustrated example of a photoelectric system comprising a photoelectric cell 4 included in a relay circuit consisting of a source of current 5 and a relay 6. The relay 6 controls by means of its contact I a secondary circuit containing the primary winding of an igniting transformer 8, a source of v current 9, and a contact l0 which is arranged to be closed by a clockwork 33 or some other time determining device during the interval of time during which the shell passes by the target. The secondary winding of the ignition transformer is connected to a spark-gap H which is arranged in the detonating composition l2 ofthe shell.

The photoelectric cell 4 is actuated by light entering through openings l3 arranged around the circumference of the walls of the shell near the base thereof. Inside said openings is provided a prism ll of circular cross section which prism on the side thereof facing the base I5 is formed with a conical recess IS the walls of which form a conical reflector for the rays of light entering through the apertures i3 whereby the light is reflected in the direction of the longitudinal axis of the shell.- After the rays of light have passed the prism, they are concentrated by means of a lens I! upon the photoelectric cell 4. The prism together with the photoelectric arrangement and the ignition composition preferably form an insertion which through suitable screw means can be secured in the base of the shell.

The arrangement operates in the following manner. As already mentioned, the source of light 2 is ignited before the shell has flown through the calculated distance to the target. In case the shell does not hit the target but passes laterally thereof the light radiated from the source of light and reflected from the target will enter through the openings i3 and is then reflected towards the photoelectric cell 4. Before that thecontact in has been closed. When the relay 6 attracts its armature a current is therefore closed through the primary winding of the ignition transformer which then sends an ignition impulse .to the direction of movement of the shell.

through the spark-gap ll causing the shell to detonate.

The prism i6 is preferably screened off in such manner that the photoelectric cell can be actuated substantially only through light which strikes the shell from the, sides. In order to take into consideration the fact that the burst fragments of the shell have a component of movement in the direction of movement of the shell, the arrangement is preferably such that the receiving arrangement can be actuated also by light entering obliquely from before, thelight emitted' from the source of light being then also directed somewhat forwardly so that the target is struck by the light when the shell is at some distance in front of the target.

Such an arrangement is shown in Figure 4 wherein the openings 8a are inclined forwardly and positioned to direct the light emitted from the source 2 forwardly so that the target receives the light before the shell is on a level of the object being fired upon. The openings Mia are likewise inclined forwardly in the base IlEa which is formed to provide a support for the prism Ma. Thus the photo-cell 4 is capable of receiving the light emitted from the source after reflection from the target before the projectile reaches a plane through the target which is perpendicular The projectile will therefore explode a few moments before itreaches a position exactly alongside the target.

A necessary condition for the proper functioning of the above described arrangement for causing shells to burst in the air is of course that the receiving arrangement is not actuated by other rays of light than those reflected from the target, thus for instance not by the day-light. Such undesired actuation can be prevented by adjusting the sensitivity of the receiving arrangement to such a value that the day-light alone does not affect the receiving arrangement sufficiently for the latter to. actuate the ignition medium of the projectile, this sufficient actuation setting in only when the much more intensive light which is reflected from the target is added. Through such a wtting of the receiving arrangement the-sensitivity thereof is reduced, however, which in some periodically varying intensity, preferably intermittent light, and by arranging the source of light so that the target is'illuminated with such light. Figures 2 and 3 show an embodiment of this kind of shell.

The source of light can consist,'as in the embodiment shown in Figure 1, of a cartridge 2 consisting of magnesium powder arranged in the front .portion of the shell. The light openings 3 in the walls of the shell are arranged in such manner about the circumference of the shell that the light radiates through said openings in a corresponding number of entirely separate beams of light. In some cases a single opening can be provided. When theshell passes the target the separate beams of light will on account of the rotation of the shell sweep over the target in sequence, light of an intermittent character being then reflected from the target.

The light receiving arrangement which is sensitive to the intermittent light consists in the example illustrated in Figs. 2 and 3 of a photoelectric cell 4 included in a circuit comprising a source of current 5 and the input terminals of a filter arrangement. transformer I8 and two condensers i9 and 2d. The output terminals of the filter arrangement i8, I9, 20 are included in one arm of a bridge circuit comprising four copper oxide rectifiers 2| and in another arm of said bridge circuit is included the winding of the relay 6. The relay 6 controls by means of its contact II a circuit including the primary circuit of the ignition transformer 8 which circuit, as in the first embodiment, includes also the current source 9 and the contact III which is controlled by a clockwork or some other time controlling device. Thepsecondary winding of the transformer 8 is connected to the sparkgap I! which is embedded in the ignition or detonating composition.

The photoelectric cell 5 is actuated by light which enters through the numerous openings i3 provided around the circumference of the shell near the base thereof. In the same manner as in the embodiment according to Figure 1 there is arranged inside the openings i3 a circular prism it having a conical recess I6 so that theentering light is reflected by the conical surface in the light reflected from the target enters through the openings i3 and is reflected towards the photoelectric cell 4. In the'circuit which includes the photoelectric cell 4, the current source 5 and the input terminals of the filterlB, I9, 20, there is then generated an alternating current of the same frequency as that of the light reflected from the target. The alternating current passes through the filter, is rectified in the bridge circuit including the copper oxide rectiflers 2|, and is supplied to the relay 6 in the form of direct current. The relay operates closing its contact I. The contact ID has been previously closed so that on operation of the relay 6 a current will flow through the primary winding of the ignition transformer and an ignition impulse is produced in the spark-gap II.

The direct current through the photoelectric cell caused by the day light can, of course, not

pass the filter l8, I9, 20 and consequently has no influence on the relay 8. Through suitable design of the fllter it is possible to provide an arrangement wherein alternating currents having frequencies within a certain band range only are passed through the fllter for actuating the relay 6. In this manner selective operation of the light receiving arrangement can be attained so that the latter is sensitive only to intermittent light which has substantially the same frequency as the light which is radiated from the light source of the shell and reflected from the target.

I claim:-

1. In an artillery projectile carrying a bursting charge, a source of light adapted to emit rays of light towards a target, means for receiving rays of light emitted from said source of light and reflected from the target, and means sensitive to said reflected rays of light and adapted upon receipt of said reflected rays to cause detonation of the bursting charge.

2. In an artillery projectile carrying a bursting I charge, a source of light adapted to emit rays of light in a lateral direction, light sensitive means .for receiving the light from said source of light after reflection from a target when passed by the projectile, and means for detonating said bursting charge upon receipt by said light sensitive means of the light reflected from the target.

3. Anartillery projectile according to claim 2, comprising also means for screening oil said light sensitive means in such a manner that the latter can be actuated exclusively by reflected light striking the projectile from the side.

4. An artillery projectile according to claim 2, comprising also means for screening 011 said source of light in such a manner that the light is emitted substantially only in lateral directions. 7

5. An artillery projectile according to claim 2, comprising also a device adapted to cause ignition of said source of light, and means for determining the moment of operation of said ignition causing device.

6. In an artillery projectile carrying an ignition composition for causing bursting thereof, a source of light adapted to emit rays of light towards a target, means for receiving rays of light emitted from said source of light and reflected from the target, light sensitive means operable to actuate the ignition composition upon receipt of said reflected rays of light, and time controlled means for preventing actuation of the ignition composition by said light sensitive means until after a predetermined point of time.

"I. An artillery projectile according to claim 6, wherein the time controlled means is operable to permit actuation of the ignition composition only during a predetermined interval of time.

8. In an artillery projectile carrying a bursting charge, a source of light adapted to emit rays of light towards the target, openings in the side walls of the projectile, an optical equipment for .receiving the reflected rays of light entering sideways through said openings, said optical equipment being adapted to reflect said rays of light in the direction of the longitudinal axis of the p'ro-' jectile' while concentrating the same, and means comprising a light sensitive part operable upon receipt of said concentrated rays of light to cause detonation of the bursting charge.

I 9. An artillery projectile according to claim 8, wherein the light sensitive part consists of a photo-electric cell.

10. An artillery projectile according to claim 8, wherein the optical equipment comprises a prism having a conical reflecting surface and located centrally inside the light openings.

11. In an artillery projectile carrying a bursting charge, a source of light arranged to emit light of a periodically varying intensity towards a target, means for receiving rays of light emitted from said source of light and reflected from the target, and means sensitive to light of the nature of the reflected light and adapted upon receipt of 12. An artillery projectile according to claim 11, wherein the source of light and at least one opening in the projectile are operable to project intermittent beams of light upon the target by rotation of the projectile.

13. An artillery projectile according to claim 11, wherein the source of light shines with a stable or constant intensity and is screened oil in such such light to cause detonation of the bursting charge.

a manner that a number of separate 'beams of light radiate in a lateral direction, wherebyon account of the rotation of the shell the target is illuminated in sequence through the various beams of light and the moments of illumination are separated through dark intervals.

14. An artillery projectile according to claim 2 including means for screening oil the light sensitive means in such a manner that the latter can be actuated exclusively by reflected light coming obliquely from a position in front of the projectile.

'MAURITZ V08. 

